We all use “age of acquisition” data in our daily practice—it helps us decide which errors are “typical” for a given age, which kids require further assessment, who requires intervention, and after that which sounds to treat and in which order. But should we be using the normative data we use for our English-speaking clients for kids who speak other languages? Not when we have data available for languages across the world—which we do!

This study provides a cross-linguistic review of children’s acquisition of consonants in 27 languages. The authors reviewed 64 studies from 31 countries to inform practicing SLPs’ expectations of children’s speech sound development across languages. They include:

Average age of acquisition data on each pulmonic consonant (those that use air from our lungs and move outward; includes all sounds in English) and each nonpulmonic sound (clicks, implosives, and ejectives);

Average age of acquisition of consonant phonemes, organized by manner and place;

Percentage of consonants correct (PCC) across 12 languages;

Percentage of vowels correct (PVC) across 5 languages;

Percentage of phonemes correct (PPC) across 2 languages; and

Early-middle-late data for 4 languages

They found that kids acquire most of the world’s consonants by the time they’re 5, and that plosives, nasals, and nonpulmonic consonants are generally acquired before trills, flaps, fricatives, and affricates.

Once the authors looked at the data as a whole, they also considered four languages specifically: English, Japanese, Korean, and Spanish. They found that the general patterns were the same across languages, however there was some variability in which consonants were not acquired by age 5 (see Figure 2 of the paper for a handy chart of consonant phonemes acquired from 2–6 years of age).

This study definitely deserves a look if you’re working with kids who speak a range of languages. It can serve as a resource not only for the languages included within the review, but also languages with no available data. SLPs can use this information and the overall patterns of speech sound development to decide what is “typical” across languages and to inform their clinical decisions.

EDIT DECEMBER 2018: There’s more to this article that you may want to consider. See here.